Sewing-machine.



PATENTED SEPT. 4, 1906.

H. MUNDLOS.

sswme MACHINE.

APPLICATION FILED FEB. 23, 1906.

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NO- 830,353. PATENTED SEPT. 4, 1906. H. MUNDLOS. SEWING MACHINE APPLICATION FILED FEB.23, 1906.

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LIGATION FILED rm.

4 SHEETS-SHEET No. 830,353. A PATENTED SEPT. 4, 1906.

H. MUNDLOS. SEWING MACHINE.

LIOATION FILED FEB.

UNIEED STATES PATENT @FFIGE.

SEWING-MACHINE.

Specification of Letters Patent.

Patented Sept. 4, 1906.

Application filed February 23,1906. Serial No. 302,370.

To all whom it may concern.-

Be it known that I, HEINRICH MUNDLos, a subject of the King of Prussia, German Emperor, residing at Magdeburg-Neustadt, Kingdom of Prussia, and German Empire, have invented new and useful Improvements in Sewing-Machines, of which the following is a specification.

My invention has reference to sewing-machines, and relates more particularly to a device for guiding the needle-thread and taking the same from the spool, whereby the thread is uniformly and tightly drawn and enabled properly to enter the work, smooth running of the machine being at the same time insured. In prior devices for the same purpose swinging levers are generally employed, which in moving in the one direction tighten the thread and in moving in the other direction release it. Owing to the reversal in motion of the levers smooth running of the machine is greatly interfered with. For guiding the thread and winding the same from the spool use has also been made of rotating eccentric plates or rotary pins, over which the thread to be guided is passed. lVith these devices the defect is that the thread has always been passed over the takeup, and thus has to partake constantly of the motion, whereby the speed with which the take-up can work is diminished. Tightening of the thread with these contrivances is effected by drawing it over segments or the like, which lengthen the path, whereby naturally the increasing amount of friction detrimentally increases the tension of the thread. Finally, with all these prior devices there is the inconvenience that the time which serves for tightening or unwinding the thread occupies a great part of the time of rotation of the driving-shaftthat is, the time in which the needle moves up and down. In consequence only a short period remains for the work of the shuttle, so that the thread enters the work very quickly, and therefore not so reliably, as it is only in a loose condition for a short period. All these defects are entirely overcome according to my present invention. The thread, which receives special guidance, is during an interval, which relatively to the time of rotation of the driving-shaft is but short, seized by a rotating cam plate or segment, raised, tightened, and wound off the spool. The friction of the thread is but small and always remains uniform and the thread after the short period of tension in a position of rest.

Certain forms of construction of the invention are shown in the accompanying drawings, in which Figure 1 is a front elevation of the head of a sewing-machine with front plate removed, with the guide-slot for the thread running concentrically with the shaft of the machine and with concentrically-moved cam-plate, the latter being shown during gripping and release of the thread. Fig. 2 is a side elevation of the machine-head, the camplate taking through the guide-slot of the guide-piece being shown in the moment of gripping the thread. guide-piece and cam-plate, the latter being shown in the moment of release of the thread. Fig. 4 shows the machine-head as illustrated in Fig. 1, the guide-slot of which, however, is bowed out at one part. Fig. 5 is a front elevation of the machinehead with guide-slot running concentrically with the machineshaft and with a cam operating eccentrically on the cam-plate. Figs. 6 and 7 show the form of construction illustrated in Fig. 5, but with the plate with cam in other positions. Fig. 8 is a cross-section on the line A A of Fig. 6. Fig. 9 shows a front elevation of a portion of the machine-head, the front plate being removed, with guide-slot located eccentrically t0 the machine-shaft and with concentrically-moving cam plate or segment.

The slot 7c, in which the thread passing from the spool to the needle is guided, runs, as the various figures show, perfectly centrally to the shaft a of the machine in the guide-bridge 0. The cam-plate b, secured to the shaft a, is either bifurcated at the end in well-known manner, and thus during a portion of its rotation takes round the guide bridge 0, and thus also the slot 75, located therein, from both sides, or the slotted guidebridge 0 can be provided with agap in the middlethat is, be dividcd-this not being shown, however. In this latter case the camplate need not be terminally bifurcated; but its end takes through the gap in the guidebridge and during the rotary motion slides for a time along the guide-slots crossing the said gap. The length of the cam-plate is approxi mately such that it registers with the outside edge of the guide-bridge 0. The length of the slot is may be adjusted above by a stop. In the constructive forms illustrated in Figs.

Fig. 3 is a plan of a portion of the I 1 to 3 a pin or screw p is shown, by way of example, for this purpose, by which the thread when raised by the cam-plate b in the slot is held and then struck off by the end of the cam-plate, Figs. 1 and 3. The length of the guide-slot lc,and thus the len th of the thread drawn off, can thus be acjusted as desired by the pin or screw 1) being set higher or lower in the guide-bridge, whereby the thread is thrown off sooner or later, as required.

In the constructive form shown in Fig. 4 the guide-slot k for the thread is provided with a bend or recess 1'. The thread, seized by the cam-plate b and raised in the slot lcthat is, pushed up it-immediately it reaches the recess 1' will be pressed into it and, as Fig. 4 shows, held therein until the cam-plate b has passed this part, whereupon the now released portion of thread which corresponds to the length of the thread requisite for further working will descend in the slot 7c. The thread is thus here alsodrawn tight by the cam-plate only during a short part of the :0- tation of the latter, being then at oncereleased again.

In the constructive forms shown in Figs. 5

v to 8 the thread guided in a slot located concentrically with the machine-shaft is seized periodically by an eccentrically-guided cam s, raised, tightened, and wound off the spool. The cam s, which is mounted on the segmental plate I), secured to the machine-shaft a, can be shifted through a certain distance and is furnished at the rear end with an eye or frame t. In the frame i there is mounteda cam to, which is secured to the pin 0, provided on the cam b. To the cam 10 the connectingbar 61 is secured, which latter is jointed at its other end to the needle-bar e and thus connects the latter with the cam u, pivoted to the plate I).

The method of operation is as follows: On rotation of the machine-shaft a, and thus of the segmental plate I), the cam 10 in the frame 75 of the cam s, which slides on the plate 5, will be set in rotation, and will thus cause the cam s to slide to and fro on the plate I). In Fig. 5 is shown, by way of example, how the thread g, guided in suitable manner, is seized by the cam s, mounted on the plate I), and raised in the slot 7: of. the guide-bridge 0. The plate 5 moves with the cam s in the direction of the arrow and slides along the slot is of the bridge from the cam s and slides down. The

thread will now be prevented by the outer segmental edge of the following cam b from fully sliding down in the slot kuntil the eye of the needle has entered the fabric-that is to say, has nearly reached its lowest position, Fig. 7. The thread 9 is only now fully free and able to slide down the slot k unobstructed, so that the portion of the thread necessary for forming the loop can be readily drawn, loosely and without any particular friction. As soon as this has been done the cam will again have assumed its position at the bottom end of the slot k, whereupon the described procedure can commence anew. In view of the eccentric form of the camplate which draws off the thread a special stop at the top part of the slot it, through which the thread is pushed off by the cam at the proper moment, is rendered unnecessary. Such a stop, in the form ofapin or screw or recess, whereby the length of the slot also might be adjusted, could, however, be provided here also without any special difficulty.

In the constructive form shown in Fig. 9 the slot 10 is arranged eccentrically in the bridge 0. The guide along which the segment or plate 1) slides is formed by aseparate piece secured to the front of the machinehead. This separate piece is recessed at the periphery, the recess being covered by a narrow strip n. This strip n, in conjunction with the guide-piece, forms the slotted bridge k 3. Through the slot 7c the thread from the spool is guided and then conducted to the thread-guide of theneedle-bar. The method of operation of the device is as follows: The thread 9 lies normally at the bottom of the slot is. Immediately the segment or plate I) is rotated by the shaft a the end of the plate 1), moving along the slot is from below, seizes the thread g, resting in the slot. The thread is thus raised, tightened, and wound off the spool, being guided upward in the slot is, reposing on the end of the plate I). The slot 76 lies eccentrically of the driving-shaft of the plate I), the thread reposing on the end of the latter being removed the farther from the axis of rotation the higher the plate b ascends. After the plate I) has raised the thread 9 to a certain extent the thread consequently slides from the plate downward until it again rests in the lowest part of the slot is. The end of the plate I) is carefully shaped so as to facilitate sliding off of the thread.

It is obvious that by means of my invention tightening and winding off of the thread can be done in rapid succession, so that the speed of the sewing-machine can be increased without there being any danger of a faulty stitch.

With the form shown in the drawings only about one-fourth of the whole rotation is necessary for drawing the thread. During the remaining period, therefore, the thread can enter the work with certainty. The I0- tating cam-plate insures smooth running of the machine.

What I do claim as my invention, and desire to secure by Letters Patent, is-

1. In a sewing-machine, in combination,a needle-bar, a rotatable shaft, a member actuated by said shaft to drive the free end of said member in acurved path, an operative connection between said member and needlebar, a guide-piece having a curved threadguiding slot conforming throughout the greater portion of its length to substantially the path of travel of the member end, and means acting near the end of said guiding-slot for releasing the thread from the member; all substantially as and for the purpose described.

2. In a sewin -machine, the combination with a machine-s aft of a segment rotatably mounted thereon, a member arranged to shift eccentrically thereon during the rotation of said segment, means for shifting said member, and a slotted guide-piece for the spoolthread, up which guide the segment end travels on rotation of the shaft; all substantially as and for the purpose described.

3. In a sewing-machine, the combination with a machine-shaft of a segment mounted thereon, a sliding plate secured to the seginent, a cam pivoted to the segment and actuating the sliding plate, and a slotted guidepiece for the spool-thread, up which guide the ends of the sliding plate and segmenttravel on rotation of the shaft; all substantially as and for the purpose described.

4. In a sewing-machine, the combination with a machine-shaft of a segment mounted thereon, a sliding plate secured to the segment, a cam pivoted to the segment and actuating the sliding plate, and a slotted guidepiece for the spool-thread, up which guide the ends of the sliding plate and the segment travel on rotation of the shaft, said sliding plate being constructed and arranged to release the thread near the top of said slot, and said segment being constructed and arranged to hold the thread-loop till the needle-eye enters the fabric; all substantially as and for the purpose described In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

HEINRICH MUNDLOS.

Witnesses:

JAMES L. A. BURRELL, OTTO MAIRosE. 

